How To: Valve Lash Adjustment for the Piaggio 150 LEADER Engine

This procedure applies to all Piaggio 150 LEADER engine applications. Specific disassembly/assembly instruction and tips are based on ET4 construction. Other Piaggio models may require their own specific chassis disassembly/assembly instruction, but all engine disassembly/assembly instruction is common to the 150 LEADER engine.

Time Required: 2 hours
Skills Required: Use of hand tools (screw driver, fixed wrench, socket driver, feeler gauge)
Degree of Difficulty: Easy to Moderate
Parts required: Slight chance of uncovering a damaged rocker cover O-ring seal
Actual complete itinerary of tools used:

Valve lash can only be set on a cold engine, so let the scooter sit overnight
Remove the right-hand-side rear fender skirt
Remove the exhaust pipe
Remove the fan shroud

Remove the cooling fan

Remove the spark plug/rocker cover access hatch
Remove the storage bucket from under the seat
Disconnect the oil run-off hose from the oil run-off cover

Remove the lower shock absorber bolt

Remove the 4 rocker cover bolts by rotating the engine to gain access to the bolts

Remove the rocker cover by simultaneously rotating the engine and working the rocker cover through the access opening
Align the timing marks on the fan with the edge of the machined surface on the crankcase

Verify the 2V reference mark on the cam is aligned with the reference point
If the marks are not aligned, rotate the fan one full revolution

Adjust the valve clearance
Intake 0.004in (0.10mm)
Exhaust 0.006in (0.15mm)
mongoose wrote:
Valve Lash Tutorial:
With a screwdriver in the adjustment screw slot, loosen the lock nut. Slide an appropriate sized (.004 or .006in) feeler gauge under the adjustment screw, and turn the screw until you get a slight drag on the feeler gauge. While still holding the screwdriver in the slot, tighten the nut and double check the lash with the feeler gauge to make sure it didn't shift when tightening.

Inspect the rocker cover gasket for defects, and replace if warranted

Refit the rocker cover and torque the 4 bolts to 8.1-9.6 ft-lbs (11 – 13 nm)
Refit all remaining parts in reverse order of removal

Copyright 2006 Gary (DBA Addicted) All Rights Reserved

Last edited by addicted on Mon Jan 16, 2006 5:46 am; edited 1 time in total